.. _examples-meteoinfolab-meteo_analysis-hcurl_hdivg: ************************ Vorticity and divergence ************************ Calculate vorticity and divergence from u and v wind components using ``vorticity()`` and ``divergence()`` functions. :: fn = os.path.join(migl.get_sample_folder(), 'GrADS', 'model.ctl') f = addfile(fn) u = f['U'][0,0,:,:] v = f['V'][0,0,:,:] lat = u.dimvalue(0) lon = u.dimvalue(1) glon, glat = np.meshgrid(lon, lat) dx, dy = meteolib.lat_lon_grid_deltas(glon, glat) vort = meteolib.vorticity(u, v, dx, dy) divg = meteolib.divergence(u, v, dx, dy) levs = arange(-3e-5, 3e-5, 1e-6) subplot(2,1,1,axestype='map') geoshow('continent') contourf(lon, lat, vort, levs) title('Vorticity') colorbar(orientation='horizontal', aspect=50) subplot(2,1,2,axestype='map') geoshow('continent') contourf(lon, lat, divg, levs) title('Divergence') colorbar(orientation='horizontal', aspect=50) .. image:: ../../../_static/vorticity_divergence.png